1. Field of Invention
The present invention relates to a method for providing antimicrobial properties to composite yarns, composite fabrics or composite articles in a simple post-production process, and the antimicrobial composite yarns, fabrics or articles provided therefrom.
2. Discussion of the Background
There are currently many types of antimicrobial fiber based products on the market. There are two basic methods for providing antimicrobial properties: 1) a poisoning method and 2) a contact kill method. In the poisoning method, the products are conventionally prepared by the incorporation of silver ions (either in the form of salts or as silver ion containing ceramics) onto the surface of the product or, in the case of polymeric based products, into the interior of the polymer by addition to the polymer melt. The silver ions then infiltrate the microbes and prevent reproduction. The downside to this method, of course, is that it takes time and the silver ions are naturally depleted, as they must come off of the product and infiltrate the microbe in order to work.
In the contact kill method, an antimicrobial agent is applied to the external surface of individual fibers or yarns or dissolved in a polymer melt prior to formation of the fibers or yarns, which upon contacting the microbe causes its death. U.S. Pat. No. 5,567,372 discloses the use of a siloxane quaternary ammonium salt based antimicrobial agent by incorporation into the polymer melt prior to fiber formation. U.S. Patent Application Publication 2003/0064645 discloses the preparation of biocidal polyester fabrics, fibers and other materials using a process that requires treatment of the polyester to provide active functional groups to which a heterocyclic N-halamine is then covalently bonded to render the polyester antimicrobial. U.S. Pat. No. 6,596,657 discloses a method for providing antimicrobial properties particularly for polypropylene and nylon containing fabrics by initial phosphonylation of the polymer fiber surface, or for non-modified surfaces by using a non-volatile salt of an antimicrobial agent such as triclosan, or by complexing iodine with a polymer containing grafted amide-bearing chains. However, all of these methods have in common the need to create the antimicrobial properties at the polymer level, either during preparation of the polymer itself, or by surface modification of the polymer fibers by chemical reaction.
In the area of composite fibers, some effort has been expended to create antimicrobial products. Since composite fibers are often used to prepare cut-proof gloves and other articles often used in meat packaging and similar industries where there are potentially high levels of bacteria, an antimicrobial composite fiber product would be very useful. U.S. Pat. No. 6,351,932; WO 99/35315; and U.S. Pat. No. 6,266,951 each disclose antimicrobial properties in a composite fiber. However, in each case, these properties are generated by forming the composite fiber from a component that has been provided with antimicrobial properties prior to incorporation into the composite fiber. Thus, in each of these cases, it is necessary for the fiber manufacturer to either purchase the antimicrobial component for use in preparation of the composite fiber, or to prepare the individual antimicrobial component themselves, prior to incorporation into the composite fiber.
In each of U.S. Pat. Nos. 6,384,254 and 5,707,736 are described methods for treating fabrics with an antimicrobial composition. U.S. Pat. No. 6,384,254 discloses the use of a quaternary ammonium salt containing polysiloxane solution to treat a fabric by dipping, spraying or roll coating to give a controlled coating weight of the antimicrobial on the fabric, followed by drying with blowing hot air or in a heating furnace at 100-150 C. In U.S. Pat. No. 5,707,736 is described a continuous process for treating a fabric by immersion of the fabric in a tub of diluted antimicrobial agent, followed by pressing to partially dry, followed by drying in a hot air blowing chamber or hot drum chamber at a temperature of up to 120 C., followed by winding of the fabric, which is then used as a dressing or support. However, again each of these methods is used by the fabric manufacturer using equipment and conditions not readily available to the ordinary consumer and typically not involving articles of finished goods containing multiple types of fibers, yarns or other materials.
Accordingly, there is a need for a method for providing antimicrobial properties to yarns, fabrics and finished articles containing two or more different types of fibers or yarns (i.e. composite yarns, composite fabrics or composite articles, respectively), which can be readily performed by the consumer, or by the manufacturer after production of the finished product.